ProtologueSp. pl. 2: 972 (1753).FamilyPoaceae (Gramineae)
Chromosome number2n = 20Vernacular namesJob’s tears, adlay (En). Larmes de Job, larmilles, herbe à chapelets (Fr). Lágrimas de Job, lágrimas de Nossa Senhora, erva dos rosários (Po). Mtasubihu, mtasbihi (Sw).Origin and geographic distributionJob’s tears is indigenous to southern and eastern Asia. It has been cultivated since ancient times, 3000–4000 years ago in India, 2000 years ago in China, and was very important before maize and rice became widespread staple foods. At present Job’s tears is cultivated as a minor cereal crop throughout the tropics and subtropics, especially in Asia. Plants escaped from cultivation occur as weeds. In Africa Job’s tears is naturalized in most countries but only very occasionally cultivated (e.g. in Liberia).UsesTypes of Job’s tears with soft-shelled false fruits can be easily husked and have large grains which are eaten in the same way as rice, alone or mixed with it. They can be substituted for rice in all foodstuffs. The grain can also be roasted before husking and then used in porridge, cakes, soups and other foods or in the preparation of sweets. Dough made from the flour will not rise because of the absence of gluten. A good mixture for bakery purposes is 70% wheat flour and 30% Job’s tears flour. The raw grain tastes sweet and is often eaten as a snack. In Africa Job’s tears is considered a famine food. Both alcoholic and non-alcoholic drinks are prepared from it. A beer made from the pounded grain is popular among Indian hill tribes and in the Philippines.The whole grain and the bran are fed to poultry and the flour can replace maize flour in poultry feed. Job’s tears is often given as a fodder, especially for cattle and horses. It is suitable for silage, and straw and leaves are used for thatching.The grain and flour of Job’s tears are easily digestible and given to people in weak condition. They are believed to have medicinal value with diuretic, depurative, anti-inflammatory and antitumour activity. A decoction of the leaves is drunk against headache, rheumatism and diabetes. Sap of the stem is applied against insect bites. A decoction of the roots is used as a vermifuge and to treat dysentery, gonorrhoea and menstrual disorders.Almost everywhere where Job’s tears grows, the decorative, hard-shelled false fruits of the wild types are used as beads for necklaces, rosaries, rattles, curtains etc., and in Africa they are often worn at ritual and religious occasions. The whole inflorescence is sometimes used in dried flower arrangements.PropertiesWhole grain of Job’s tears contains per 100 g edible portion: water 8.9 g, energy 1394 kJ (333 kcal) protein 10.4 g, fat 5.3 g, carbohydrate 66.5 g and fibre 10.5 g. The hulled grain contains per 100 g edible portion: water 11.6 g, energy 1511 kJ (361 kcal), protein 14.8 g, fat 4.9 g, carbohydrate 66.9 g, fibre 0.5 g, Ca 47 mg, P 254 mg, Fe 6.0 mg, β-carotene 0 mg, thiamin 0.26 mg, riboflavin 0.19 mg and niacin 4.7 mg (Leung, Busson & Jardin, 1968). The content of essential amino acids per 100 g protein (16 g N) is: tryptophan 0.5 g, lysine 1.9 g, methionine 2.6 g, phenylalanine 4.9 g, threonine 3.0 g, valine 5.7 g, leucine 13.6 g and isoleucine 3.9 g (Busson, 1965).The root contains coixol, which is analgesic and sedative. Methanolic extracts of the grains showed an antiproliferative effect on human lung cancer cells in vitro and in vivo and might reduce the risk of tobacco-induced lung tumorigenesis. The grains might also be beneficial for the treatment of allergic disorders.BotanyErect, perennial, strongly tillering grass up to 3 m tall, often cultivated as an annual; stem (culm) filled with pith, glabrous, branched in the upper part. Leaves alternate, simple and entire; leaf sheath short, glabrous or with long hairs at apex; ligule short and membranous; blade linear to ovate-lanceolate, 8–100 cm × 1.5–7 cm, base rounded to almost cordate, apex acute, margins rough, upper surface smooth or scabrid, midrib prominent. Inflorescences in axils of upper leaves, solitary or 2–7-fascicled and arranged panicle-like, on peduncle 3–6 cm long, consisting of 2 unisexual racemes; female raceme enclosed by a hollow, bony, globular to ovoid-ellipsoid cupule 5–15 mm long, shiny, white, pale brown, grey, bluish or black, with a sessile spikelet accompanied by 2 barren pedicels; male raceme 3–5 cm long, exserted from the mouth of the cupule, with about 10 spikelets borne in pairs or threes, one pedicelled, the other(s) sessile. Female spikelet 2-flowered, with orbicular glumes, lower floret reduced to an orbicular lemma, upper floret with membranous lemma and palea and superior ovary with 2 stigmas exserted from the mouth of the cupule; male spikelet lanceolate to ellipsoid, 7–8 mm long, 1– 2-flowered, lower glume winged, upper glume boat-shaped, each floret with membranous lemma and palea and 3 stamens. Fruit a caryopsis (grain) enclosed by the cupule (shell of false fruit), globose, dark red in hard-shelled types, pale brown in soft-shelled types.Coix comprises about 5 closely related species, all native in Asia, but some have been introduced elsewhere. Mainly based on characteristics of the false fruit, 4 varieties have been distinguished in Coix lacryma-jobi, but only var. lacryma-jobi occurs in Africa; it is characterized by ovoid, hard, smooth false fruits. Most agricultural information (from outside Africa) concerns var. ma-yuen (Rom.Caill.) Stapf, with ovoid to pear-shaped, quite soft, striate false fruits; it is cultivated as a cereal.Job’s tears takes about 1–2 weeks to germinate, depending on the moisture content of the soil. Both self-pollination and cross-pollination are possible, with the latter usually being predominant. Total crop duration is 4–6(–8) months. When most of the seeds are ripe, the plant starts to dry. Job’s tears follow the C4-cycle photosynthetic pathway.EcologyJob’s tears occurs wild in swampy locations and along watercourses. It is a quantitative short-day plant and requires high temperatures, abundant rainfall and reasonably fertile soils. In the tropics it occurs from sea-level up to 2000 m altitude, in Africa often around villages and on abandoned fields.ManagementJob’s tears is usually propagated by seed. The 1000-seed weight is 80–90 g. Seed is dibbled, 5 cm deep, at the start of the rains, after ploughing or hoeing the field. Row spacing is 40–80 cm, and seed rate 7–15 kg/ha. When cultivated as an intercrop, it is sown at random or plants are grown along field borders. Propagation by cuttings is possible and recommended for fodder production. Propagation by seed gives deeper rooting, and, consequently, better drought tolerance and higher grain yield.Weeding is necessary up to 60 days after sowing or until Job’s tears has reached a plant height of 40 cm. In general, plants are not given much care, but when young they need abundant water. They respond well to application of manure; chemical fertilizers or insecticides are not used.The most serious disease of Job’s tears is smut (Ustilago coicis) which destroys the ovaries. Smut can severely damage crops and therefore seed treatment with fungicide or with hot water (60–70°C) for at least 10 minutes before sowing is recommended. Another important disease of Job’s tears is leaf blight (Bipolaris coicis); control measures include burning of crop residues, spraying of fungicides and the use of more resistant cultivars. Tar leaf spot (Phyllachora coicis), rust (Puccinia operata) and Ustilago lachrymae-jobi (synonym: Sporisorium lachrymae-job) are some of the other diseases attacking Job’s tears. Rats, birds and sometimes grasshoppers and termites may cause considerable losses.Job’s tears is normally harvested 4–6 months after sowing, depending on the cultivar and the season. Usually, whole plants are cut at the base when the grain is ripe. The stubble can be left in the field and will then tiller again; the new fresh leaves are an excellent fodder. Normal yield of husked grain varies from 2–4 t/ha. The hulling percentage is 30–50%. If cultivated for fodder, several cuts per year are possible.After threshing and husking, which is done manually or with the same tools as for rice, the grain is sun-dried on mats. Under humid conditions, the storability of the grain is limited, but is better for whole than for husked grain.Genetic resources and breedingThe largest germplasm collections of Job’s tears are held in China (Institute of Crop Germplasm Resources (CAAS), Beijing, 87 accessions) and the Philippines (Institute of Plant Breeding, University of the Philippines Los Baños (UPLB), College, Laguna, 31 accessions). The greatest variation in wild forms occurs in India and Myanmar, in cultivated Job’s tears in South-East Asia. In the course of time, Job’s tears has been selected by farmers for easy husking, resulting in var. ma-yuen. However, the crop has a relatively long growing season, shows uneven ripening and variable yields. Nevertheless, the large variability in Job’s tears offers opportunities for breeding programmes, e.g. to obtain resistance against smut disease. In Japan selection work focuses on the use as a fodder. In Brazil a high-yielding ‘dwarf’ cultivar, probably introduced from Japan, has been selected and distributed.ProspectsAlthough enjoyed locally by many people, Job’s tears is still decreasing in popularity in favour of higher-yielding cereals, mainly maize and rice. However, because it is less susceptible to diseases and pests, it can be grown where other crops are difficult to cultivate, it does not need much care, it is highly nutritious and has promising medicinal properties, Job’s tears deserves more research attention.Major references• Burkill, H.M., 1994. The useful plants of West Tropical Africa. 2nd Edition. Volume 2, Families E–I. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 636 pp. • Chang, H.C., Huang, Y.C. & Hung, W.-C., 2003. Antiproliferative and chemopreventive effects of adlay seed on lung cancer in vitro and in vivo. Journal of Agricultural and Food Chemistry 51: 3656–3660. • Clayton, W.D. & Renvoize, S.A., 1982. Gramineae (Part 3). In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. pp. 451–898. • Mello, L.V., Silva, W.J., Medina Filho, H.P. & Balvvé, R., 1995. Breeding systems in Coix lacryma-jobi populations. Euphytica 81: 217–221. • van den Bergh, M.H. & Iamsupasit, N., 1996. Coix lacryma-jobi L. In: Grubben, G.J.H. & Partohardjono, S. (Editors). Plant Resources of South-East Asia No 10. Cereals. Backhuys Publishers, Leiden, Netherlands. pp. 84–87.Other references• Busson, F., 1965. Plantes alimentaires de l’ouest Africain: étude botanique, biologique et chimique. Leconte, Marseille, France. 568 pp. • Chang, S.W. & Hwang, B.K., 2002. Relationship of host genotype to Bipolaris leaf blight severities and yield components of adlay. Plant Disease 86(7): 774–779. • Gurib-Fakim, A., Guého, J. & Bissoondoyal, M.D., 1997. Plantes médicinales de Maurice, tome 3. Editions de l’Océan Indien, Rose-Hill, Mauritius. 471 pp. • Hsu, H.-Y., Lin, B.-F., Lin, J.Y., Kuo, C.-C. & Chiang, W., 2003. Suppression of allergic reactions by dehulled adlay in association with the balance of Th1/Th2 cell responses. Journal of Agricultural and Food Chemistry 51: 3763–3769. • Leung, W.-T.W., Busson, F. & Jardin, C., 1968. Food composition table for use in Africa. FAO, Rome, Italy. 306 pp. • Naku Mbumba, M.D., Walangululu, M. & Basiloko, M., 1984. Comportement des plants issus de différents modes de propagation du coïx. Tropicultura 2(3): 95–98. • Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp. • Numata, M., Yamamoto, A., Moribayashi, A. & Yamada, H., 1989. Antitumor components isolated from the Chinese herbal medicine Coix lachryma-jobi. Phytochemistry 28(3): 883–886. • Purseglove, J.W., 1972. Tropical crops. Monocotyledons. Volume 1. Longman, London, United Kingdom. 334 pp. • Watt, J.M. & Breyer-Brandwijk, M.G., 1962. The medicinal and poisonous plants of southern and eastern Africa. 2nd Edition. E. and S. Livingstone, London, United Kingdom. 1457 pp.Sources of illustration• van den Bergh, M.H. & Iamsupasit, N., 1996. Coix lacryma-jobi L. In: Grubben, G.J.H. & Partohardjono, S. (Editors). Plant Resources of South-East Asia No 10. Cereals. Backhuys Publishers, Leiden, Netherlands. pp. 84–87.Author(s)